Prolongation of life-span by restricted feeding of laboratory animals is an often repeated and well accepted finding. Little data exists relative to the physiological modification of cardiac performance associated with food restriction. Animals in the present series have been maintained on life-long food restriction by ad-libidum feeding on an every other day sequence (EOD) and are compared with cohort matched controls. Preliminary data shows a premature age deficit and appears to indicate that senescent age changes in myocardial performance can be made to occur out of phase with chronological age by food restriction, i.e., occur at an earlier age.